The aim of this proposal is to extend the existing magnetic-resonance force microscopy detection scheme by application to light-generated, short-lived triplet states as paramagnetic probes. For this purpose, initially diamagnetic chromophores are immobilized on a surface and are photo-excited into their triplet state (S = 1). This novel detection scheme potentially has the following advantages: (i) generation of triplet states by photo-excitation results in strong initial electron-spin polarization, and hence strong magnetization, on a microsecond to millisecond time scale even at comparatively high temperatures; (ii) the scheme allows repetitive photo-excitation thus leading to significantly enhanced signal-to-noise ratio; (iii) the combination of light-excitation and cantilever-detection minimizes unwanted perturbations due to light scattering or background fluorescence, and (iv) stable paramagnetic probes that are susceptible to secondary chemistry are not needed. After successful implementation of the method, we will test two applications: First, the setup will be used (i) to quantify aptamer–substrate binding constants and (ii) to scan triplet-labeled cells for protein localization purposes. With the results, we aim towards all-purpose applications.